Preheat oven to 325F. Trim fat from beef. In bowl, combine anise, oil, 2 tablespoons mustard, garlic, 3/4 teaspoon salt, and 1/4 teaspoon ground black pepper; set aside 3 tablespoons oil mixture. Place beef on rack in a shallow roasting pan. Spread remaining oil mixture on top and sides. Roast 1-1/3 to 2-1/4 hours for medium-rare (135F internal) or 2-1/4 to 2-3/4 hours for medium (150F).
Meanwhile, combine dried fruit, onions, 1/3 cup juice, and reserved oil mixture. Fold 18x36-inch heavy foil in half to 18-inch square; place fruit mixture in center. Doublefold opposite foil edges, leaving room for steam. The last 1 hour of roasting time place packet beside roast. The last 30 minutes place pears in pan beside roast; stir once.
Transfer roast and pears to platter; cover, let stand 15 minutes. Remove foil packet from oven; set aside. Reserve 1 tablespoon fat in roasting pan; whisk flour into fat. Whisk 2 cups juice with 1 tablespoon mustard; add to pan. Place pan over two burners on medium-high heat. Whisk until thickened and bubbly, scraping up browned bits; whisk 1 to 2 minutes more. Strain; serve with beef,fruits, and onion. Garnish with rosemary. Serves 12.